Background: Thyroid cancer is the most common endocrine cancer, in which genetic mutations play a major role. We studied thyroid stimulating hormone (TSH) receptor gene polymorphism (rs179247 and rs12101255) in papillary thyroid carcinoma (PTC).

Methods: The study was conducted on fifty patients with documented PTC. Patients with thyroid nodules were selected from Alexandria University hospital outpatient clinics after excluding hyperthyroidism, autoimmune thyroid diseases, and non-suspicious nodules. Eligible patients were subjected to total thyroidectomy in the head and neck and endocrine surgery unit. DNA, extracted from formalin fixed paraffin embedded normal and malignant thyroid tissues, was analyzed by real time polymerase chain reaction using TaqMan® Genotyping Assay.

Results: No difference was found between normal and malignant tissues regarding TSH receptor polymorphism. No relations were found in both polymorphisms with serum TSH, malignant nodule size, multiplicity of the lesions, TIRADs staging, or Bethesda classification. Rs179247 genotype AA (vs. AG and GG: P=0.044*) was associated with extrathyroidal extension.

Conclusions: In conclusion TSH receptor polymorphism rs179247, and not rs12101255, may predict extrathyroidal extension in papillary thyroid cancer.